This movie shows the location of Mercury's magnetic equator determined on successive orbits as the point where the direction of the internal magnetic field is parallel to the spin axis of the planet. This magnetic equator is well north of the planet's geographic equator (indicated by the horizontal gray line). The best-fitting internal dipole magnetic field is located about 0.2 Mercury radii, or 480 km, northward of the planet's center. The dynamo mechanism in Mercury's molten outer core responsible for generating the planet's magnetic field therefore has a strong north-south asymmetry.

The MESSENGER spacecraft is the first ever to orbit the planet Mercury, and the spacecraft's seven scientific instruments and radio science investigation are unraveling the history and evolution of the Solar System's innermost planet. Visit the Why Mercury? section of this website to learn more about the key science questions that the MESSENGER mission is addressing.

These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy.